Some peculiarities of the ultrafine structure of the neurons of the cestode Pelichnibothrium speciosum (Monticelli, 1889) (Cestoda: Tetraphyllidea)]

In the scolex ganglia of the cestode Pelichnibothrium speciosum uni - and multipolar neurons can be found. Their neuroplasm is rich in free ribosomes. The ergastoplasmas membranes are frequently arranged in compact finger print-like structures. The nerve cells processes form tight junctions which cannot be interpreted as synaptic contacts.     

Dynamics of the X-sex chromatin in the buccal epithelial cells of pregnant women with rhesus-negative blood

The content of X-sex chromatin was studied in the buccal epithelial cells of pregnant women with Rh-negative blood. It was found that in women with a titer of Rh antibodies the amount of cells with X-sex chromatin decreases. A clinical-cytological correlation in the mother-placenta-fetus system was traced in pregnant women with a Rh antibody titer.     

Crystal structures of beta-galactosidase from Penicillium sp. and its complex with galactose

Beta-galactosidases catalyze the hydrolysis of beta(1-3) and beta(1-4) galactosyl bonds in oligosaccharides as well as the inverse reaction of enzymatic condensation and transglycosylation. Here we report the crystallographic structures of Penicillium sp. beta-galactosidase and its complex with galactose solved by the SIRAS quick cryo-soaking technique at 1.90 A and 2.10 A resolution, respectively. The amino acid sequence of this 120 kDa protein was first assigned putatively on the basis of inspection of the experimental electron density maps and then determined by nucleotide sequence analysis. Primary structure alignments reveal that Penicillium sp. beta-galactosidase belongs to family 35 of glycosyl hydrolases (GHF-35). This model is the first 3D structure for a member of GHF-35. Five distinct domains which comprise the structure are assembled in a way previously unobserved for beta-galactosidases. Superposition of this complex with other beta-galactosidase complexes from several hydrolase families allowed the identification of residue Glu200 as the proton donor and residue Glu299 as the nucleophile involved in catalysis. Penicillium sp. beta-galactosidase is a glycoprotein containing seven N-linked oligosaccharide chains and is the only structure of a glycosylated beta-galactosidase described to date.     

Mineral Composition of Wild Onions and Their Nutritional Value

Leaf accumulation of 11 microelements (Fe, Zn, Cu, Co, Mn, Ni, Pb, Cd, Sr, Cr, and Se) was studied in seven wild onion species of the genus Allium. A. flavescens Bess. accumulates five microelements (Cr, Ni, Cu, Zn, and Se) and also contains Fe, Co, and Mn at high concentrations. These features underlie the significant promise of this species as a means of procurement (nutritional adjustment of the content) of these microelements. The content of Cr in 100 g of leaves of this species is equivalent to 84% of the daily human need for this microelement. A. fistulosum L., A. odorum L., and the broad-leaved form of A. nutans specifically accumulate Cu, Zn, and Se. A. montanum Schmidt. is characterized by the accumulation of Zn. A. angulosum L. and A. schoenoprasum L. are characterized by the accumulation of Se. The broad-leaved forms of A. schoenoprasum L., A. nutans L., and A. odorum L. accumulate higher amounts of Zn and Cu than their narrow-leaved counterparts.     

Purification, and biochemical and biophysical characterization of cellobiohydrolase I from Trichoderma harzianum IOC 3844

Because of its elevated cellulolytic activity, the filamentous fungus Trichoderma harzianum has a considerable potential in biomass hydrolysis applications. Trichoderma harzianum cellobiohydrolase I (ThCBHI), an exoglucanase, is an important enzyme in the process of cellulose degradation. Here, we report an easy single-step ion-exchange chromatographic method for purification of ThCBHI and its initial biophysical and biochemical characterization. The ThCBHI produced by induction with microcrystalline cellulose under submerged fermentation was purified on DEAE-Sephadex A-50 media and its identity was confirmed by mass spectrometry. The ThCBHI biochemical characterization showed that the protein has a molecular mass of 66 kDa and pI of 5.23. As confirmed by smallangle X-ray scattering (SAXS), both full-length ThCBHI and its catalytic core domain (CCD) obtained by digestion with papain are monomeric in solution. Secondary structure analysis of ThCBHI by circular dichroism revealed alpha- helices and beta-strands contents in the 28% and 38% range, respectively. The intrinsic fluorescence emission maximum of 337 nm was accounted for as different degrees of exposure of ThCBHI tryptophan residues to water. Moreover, ThCBHI displayed maximum activity at pH 5.0 and temperature of 50 degrees C with specific activities against Avicel and p-nitrophenyl-β-D-cellobioside of 1.25 U/mg and 1.53 U/mg, respectively.     

Peroxidases from alfalfa roots: Catalytic properties and participation in degradation of polycyclic aromatic hydrocarbons

From the roots and root exudates of 3-week-old plants of alfalfa (Medicago sativa L.), anionic and cationic peroxidases differing in principal physicochemical and catalytic properties were isolated and purified. Main features of anionic peroxidases detected in the roots and root exudates were identical. Phenanthrene present in the soil used for alfalfa growing influenced the number of forms and activity of peroxidases in crude enzyme preparations but did not affect the properties of pure enzymes. In the presence of a synthetic mediator, purified peroxidases can oxidize phenanthrene and its derivatives, including potential microbial metabolites of polycyclic aromatic hydrocarbons (PAH). The fact that the enzymes excreted in root exudates in a purified form can oxidase PAH proves their participation in degradation of PAH and their microbial metabolites in alfalfa rhizosphere. These new data indicate that the processes of plant and microbial degradation of pollutants in the rhizosphere are coupled; they are relevant to understanding the molecular mechanisms of degradation of persistent pollutants by plant-microbial complexes.     

Isolation of tremelloid yeasts on glucuronate medium

D-Glucuronate-containing agar is suggested for evaluating the population density and diversity of tremelloid yeasts in natural cenoses. This medium is superior to the commonly used wort agar on which many representatives of tremelloid yeasts cannot be revealed.     

Cryptococcus festucosus sp. nov. a new hymenomycetous yeast in the Holtermannia clade

Five yeast strains belonging to the genus Cryptococcus Vuillemin were isolated from steppe plants and turf collected in the Prioksko-terrasny biosphere reserve (Moscow region, Russia). Sequence analyses of the D1/D2 domains of the 26S rDNA and of the internal transcribed spacer region revealed that these yeast strains and strain CBS 8016 have almost identical sequences and belong to the Holtermannia clade of the Tremellomycetidae (Basidiomycota, Hymenomycetes). A novel species named Cryptococcus festucosus (type strain VKM Y-2930) is proposed to accommodate these strains. Physiological characteristics and mycocin sensitivity patterns distinguishing Cryptococcus festucosus from the other species of this clade are presented.     

The effect of mutations in recB and recC genes on the precise excision of Tn5 from pNM1 plasmid genome

The affect of mutations in chromosomal genes determining the realization of RecBC and RecF pathways of recombination in E. coli K12 on the frequency of transposon Tn5 precise excision from the genome of the conjugative plasmid pNM1 has been demonstrated. The pNM1 plasmid is a derivative of R100.1 and differs from the latter in the presence of Tn5 inactivating the tet gene of transposon Tn10.     

A New Basidiomycetous Yeast Species, Cryptococcus mycelialis, Related to Holtermannia Saccardo et Traverso

A new species of the genus Cryptococcus, Cr. mycelialis (the type strain VKM Y-2863), is described based on the taxonomic study of four strains isolated from soil and plant samples collected on the South Georgia and East Falkland islands. This species differs from the known Cryptococcus species in its ability to form a true monokaryotic mycelium with pseudoclamp connections and haustoria. The species can be distinguished from the phylogenetically related and phenotypically similar species Holtermannia corniformis and Cr. nyarrowii by some assimilatory reactions, maximum growth temperature, and sensitivity to mycocins.